Ultrasonically induced microemulsion polymerization of styrene

Zhang, Chuhong; Wang, Qi; Xia, Hesheng; Qiu, Guihua

doi:10.1016/s0014-3057(02)00072-1

Cited by 45 publications

(26 citation statements)

References 26 publications

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“…1. Although polymerization may also occur, via thermally 45,46 or sonochemically generated 40,[47][48][49] free radicals, the control experiments showed that the polymerization of St and DVB was negligible under the present conditions in the absence of any chemical radical initiators, for emulsication times of up to 60 min.…”

Section: One-step Acoustic Emulsication/polymerization Under Surfactmentioning

confidence: 72%

Surfactant-free synthesis of sub-100 nm poly(styrene-co-divinylbenzene) nanoparticles by one-step ultrasonic assisted emulsification/polymerization

et al. 2015

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The synthesis of sub-100 nm polymeric nanoparticles in a surfactant-free form is currently very challenging due to the oil nanoemulsion instability in polar solvents and in the absence of stabilizers. Here we report for the first time the surfactant-free synthesis method of poly(styrene-co-divinylbenzene) nanoparticles in an aqueous environment using ultrasonic radiation. This method involves emulsification of the monomers mixture in water, followed by free-radical polymerization under pulsed or continuous acoustic fields. The local energy produced in water by cavitation effects was sufficient to: (1) generate and stabilize the monomer nanoemulsion due to mechanical forces, and (2) drive the radical polymerization due to the heat generated. The average size of the final polymer nanoparticles obtained depended: (i) inversely on the monomer/water interfacial energy, emulsification power, and (ii) directly on temperature, amount of initiator and monomer solubility. The polymer nanoparticle size distribution and shape was considerably improved upon the addition of a co-polymerizable surfactant.

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Section: One-step Acoustic Emulsication/polymerization Under Surfactmentioning

confidence: 72%

Surfactant-free synthesis of sub-100 nm poly(styrene-co-divinylbenzene) nanoparticles by one-step ultrasonic assisted emulsification/polymerization

et al. 2015

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“…The degradation observed may be related to non-ionic surfactants used in the formulation. Zhang et al [23] also reported phase separation using ultrasound in formulations with non-ionic surfactants, but the same was not observed in formulations containing cationic or anionic surfactants. The authors hypothesized that both steric effect and charges present in ionic surfactants prevented the stability loss while non-ionic surfactants stabilize only by steric hindrance thus forming a less stable system.…”

Section: Ultrasound Application Effect In Particle Sizementioning

confidence: 97%

“…It is characterized as sonic waves of frequency between 2 Â 10 4 and 10 7 Hz [23]. Many theories about its mechanism in chemical reactions are suggested, but they all propose acoustic cavitations, which occur when ultrasound waves propagate through a liquid media creating bubbles that grow and collapse.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of short cycles of ultrasound application in nanoemulsions to obtain nanocapsules

Carneiro

Cruz

Santos

2015

Ultrasonics Sonochemistry

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Ultrasound is widely used in several chemical reactions and other process, including production of nanocapsules by in situ polymerization. In this work, the main objective was to evaluate the impacts and viability of successive ultrasound application in nanoemulsions to obtain nanocapsules. Initiator potassium persulfate (KPS) concentration, number of ultrasound cycles and reaction time influences on polymerization efficiency and droplet size were evaluated. This work revealed the successful in situ production of nanocapsules using successive shorts cycles of ultrasound. Number of cycles was the only parameter that not exerted significant influence in polymerization yield. Particle size decay was observed in all nanoemulsions after the first ultrasound application, the same was not observed in further cycles. Gravimetric assessment showed remarkable increase of monomer conversion, indicating that once started polymerization continued at least until 28 days after ultrasound application. Concluding, ultrasound short cycles can be used with no harm to formulation, if carefully performed and, furthermore is a potential cost-effective route for polymerization reactions.

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“…The generation of radicals by ultrasound can also be applied in emulsion polymerization, which comprises a free-radical polymerization in a heterogeneous reaction system, yielding submicrometer polymer particles in a continuous aqueous phase. In literature a number of publications have appeared over the years on the application of ultrasound in emulsion polymerization (36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46). Ultrasound can be applied both for emulsification purposes as well as at higher conversions in the emulsion polymerization process (see HETEROPHASE POLYMERIZATION).…”

Section: Ultrasound-induced Radical Polymerizationmentioning

confidence: 99%

Ultrasound‐Induced Radical Polymerization

Kuijpers¹,

Kemmere²,

Keurentjes³

2004

Encyclopedia of Polymer Science and Technology

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Sonochemistry comprises all chemical effects that are induced by ultrasound. Most of these effects are caused by cavitations, ie, the collapse of microscopic bubbles in a liquid. The chemical effects of ultrasound include the formation of radicals and the enhancement of reaction rates at ambient temperatures. For the development of sustainable polymer processes, ultrasound is an interesting technology, as it allows for polymerizations without the use of initiator. The radicals are generated in situ by cavitation events, which enable a clean and intrinsically safe polymerization reaction. As a result of the high strain rates outside the bubble, cavitation can also induce chain scission, which provides an additional means to control the molecular weight of the produced polymer. This article discusses the possibilities, mechanisms, and challenges of several types of ultrasound‐induced radical polymerizations.

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Ultrasonically induced microemulsion polymerization of styrene

Cited by 45 publications

References 26 publications

Surfactant-free synthesis of sub-100 nm poly(styrene-co-divinylbenzene) nanoparticles by one-step ultrasonic assisted emulsification/polymerization

Surfactant-free synthesis of sub-100 nm poly(styrene-co-divinylbenzene) nanoparticles by one-step ultrasonic assisted emulsification/polymerization

Evaluation of short cycles of ultrasound application in nanoemulsions to obtain nanocapsules

Ultrasound‐Induced Radical Polymerization

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